Unable to install Mojave from USB drive on new MacBook Pro 2018

bobtrotter

macrumors newbie
Original poster
Sep 23, 2014
28
13
Hey I have a new 2018 15" MacBook Pro with High Sierra installed. I want to do a clean install of Mojave. I have followed the instructions at https://www.macrumors.com/how-to/clean-install-macos-10-14-mojave/ to create a boot disk. I have the USB drive installed and I hold down the option key and reboot the machine. I select Install Mojave (from the USB), this is the option on the right. Now instead of being greeted with a screen about installing the OS I am asked to unlock the main hard disk. If I unlock it I am taken to the main High Sierra login screen and the install is not performed. If I hit cancel I have the option to choose a startup disk and restart. I can choose Mojave however I am then presented with "The bless tool was unable to set the current boot disk" error. Images at: https://imgur.com/a/r5ADNaJ

Note: I have enabled boot from external drives in the T2 startup security menu.

What am I doing wrong here? People say I can run the internet recovery by holding down cmd and R on restart and then install Mojave from there, however I have tried this and it only downloads High Sierra.

How do I clean install from the USB? Thanks
 
Last edited:

oatman13

macrumors regular
Feb 14, 2013
228
60
Hey I have a new 2018 15" MacBook Pro with High Sierra installed. I want to do a clean install of Mojave. I have followed the instructions at https://www.macrumors.com/how-to/clean-install-macos-10-14-mojave/ to create a boot disk. I have the USB drive installed and I hold down the option key and reboot the machine. I select Install Mojave (from the USB), this is the option on the right. Now instead of being greeted with a screen about installing the OS I am asked to unlock the main hard disk. If I unlock it I am taken to the main High Sierra login screen and the install is not performed. If I hit cancel I have the option to choose a startup disk and restart. I can choose Mojave however I am then presented with "The bless tool was unable to set the current boot disk" error. Images at: https://imgur.com/a/r5ADNaJ

Note: I have enabled boot from external drives in the T2 startup security menu.

What am I doing wrong here? People say I can run the internet recovery by holding down cmd and R on restart and then install Mojave from there, however I have tried this and it only downloads High Sierra.

How do I clean install from the USB? Thanks
In addition to enabling "Boot from External USB"; why don't you change your security settings from "Full Security" to "No Security". This should allow you to boot from the drive.

After the install, you can go back and change your security settings.
 

toru173

macrumors 6502
Apr 5, 2007
303
126
You can also hold command+option+R (HT204904) to download the Mojave version of recovery and boot from there. If that key combo doesn’t pull down Mojave you may have to DFU restore your T2.

The team at the Apple Store should be able to help out!
 
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